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  <div class="section" id="module-whichdb">
<span id="whichdb-guess-which-dbm-module-created-a-database"></span><h1>11.7. <a class="reference internal" href="#module-whichdb" title="whichdb: Guess which DBM-style module created a given database."><tt class="xref py py-mod docutils literal"><span class="pre">whichdb</span></tt></a> &#8212; Guess which DBM module created a database<a class="headerlink" href="#module-whichdb" title="Permalink to this headline">¶</a></h1>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">The <a class="reference internal" href="#module-whichdb" title="whichdb: Guess which DBM-style module created a given database."><tt class="xref py py-mod docutils literal"><span class="pre">whichdb</span></tt></a> module&#8217;s only function has been put into the <a class="reference internal" href="dbm.html#module-dbm" title="dbm: The standard &quot;database&quot; interface, based on ndbm. (Unix)"><tt class="xref py py-mod docutils literal"><span class="pre">dbm</span></tt></a>
module in Python 3.  The <a class="reference internal" href="../glossary.html#term-to3"><em class="xref std std-term">2to3</em></a> tool will automatically adapt imports
when converting your sources to Python 3.</p>
</div>
<p>The single function in this module attempts to guess which of the several simple
database modules available&#8211;<a class="reference internal" href="dbm.html#module-dbm" title="dbm: The standard &quot;database&quot; interface, based on ndbm. (Unix)"><tt class="xref py py-mod docutils literal"><span class="pre">dbm</span></tt></a>, <a class="reference internal" href="gdbm.html#module-gdbm" title="gdbm: GNU's reinterpretation of dbm. (Unix)"><tt class="xref py py-mod docutils literal"><span class="pre">gdbm</span></tt></a>, or <a class="reference internal" href="dbhash.html#module-dbhash" title="dbhash: DBM-style interface to the BSD database library."><tt class="xref py py-mod docutils literal"><span class="pre">dbhash</span></tt></a>&#8211;should be used to open a given file.</p>
<dl class="function">
<dt id="whichdb.whichdb">
<tt class="descclassname">whichdb.</tt><tt class="descname">whichdb</tt><big>(</big><em>filename</em><big>)</big><a class="headerlink" href="#whichdb.whichdb" title="Permalink to this definition">¶</a></dt>
<dd><p>Returns one of the following values: <tt class="xref docutils literal"><span class="pre">None</span></tt> if the file can&#8217;t be opened
because it&#8217;s unreadable or doesn&#8217;t exist; the empty string (<tt class="docutils literal"><span class="pre">''</span></tt>) if the
file&#8217;s format can&#8217;t be guessed; or a string containing the required module name,
such as <tt class="docutils literal"><span class="pre">'dbm'</span></tt> or <tt class="docutils literal"><span class="pre">'gdbm'</span></tt>.</p>
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